The recent advancement of semiconductors and the low costs of memory IC's have made it practical to incorporate into consumer electronics imaging equipment a device for storing a frame of TV image signal in the memory and reading them out for display as a still picture. For example, ordinary TV receivers with such a device can display a given frame of movies as a still picture and can be used for various other purposes. One of the easiest ways to provide such a still picture is the use of a video tape or cassette recorder. With a VTR or VCR, it is possible to pause the playback of a recorded TV program to provide a still picture. However, this method requires the recording, tape rewinding, and playback operations, and it is too troublesome to pause the TV program being broadcast to give a still picture for taking memos for example. It is also not practical to always put the VCR in the recording condition for giving a still picture. Thus, it has been proposed to store TV image signals in an image memory, such as a solid-state memory, from which a still picture is produced by simply pressing the button at the desired scene. Such a device is easy to operate and will find a wide range of applications.
FIG. 6 shows an example of such prior art devices. The desired TV channel can be selected with a tuner 1 from the TV signals received by an antenna 1a and sent to an image amplification and demodulation circuit 2. The demodulated image signal A is supplied through a switch circuit 3 to an image output circuit 4 for driving a display or CRT 13. The demodulated image signal A is also supplied to a synchronization separating circuit 5 to put out horizontal and vertical synchronizing signals SH and SV. These signals are fed to a deflection circuit 6 to generate sawtooth current for driving a deflection yoke 14 of the CRT 13. As a result, a TV picture is displayed on the CRT 13. So far, nothing is different from the conventional TV receiver.
Indicated by a dotted line is an image processing section R for displaying still pictures. The aforementioned demodulated image signal A is converted to a digital signal in an A/D converter 7. In the period of one field or frame after the output H of a flip-flop 10, which is inverted every time a button 15 is pushed, is turned to a high level, a memory control circuit 11 puts out a write signal to an image memory 8 for writing an image signal E in the image memory 8. Upon completion of the writing, the memory control circuit 11 puts out a read signal for reading out the written image signal. This read-out image signal F is converted to an analog signal G in a D/A converter 9 and sent to the switching circuit 3. When the output H of the flip-flop is at a high level, the switch 3 is connected to a point 2 so that the image signal G from the memory 8 is sent to the image output circuit 4 and then displayed on the CRT 13 as a still picture. When the switch 15 is pushed again, the flip-flop 10 is inverted to a low level, which in turn brings the switch 3 to a point 1 for displaying an ordinary TV picture. A reference oscillator 12 supplies operation clocks to the aforementioned memory control circuit 11.